All right, I made some improvements and changes to MOTR's motrfile. Unfortunately, I'm going to have to roll one of the changes back. I thought "Oh, I can just make MOTR require pyproject-build and not need a venv for that," but no. It couldn't be that easy. Somehow that causes the test environments to try to install apparently every version of pytest. This shouldn't be a problem for end users, but it means I can't run my own tests.
That means I need to reintroduce the path field, and... let's see... I don't feel like figuring out the right way to do the installation, so I'm just leaving it pretty much as-is for now.
I also fixed up some type errors in the motrfile that weren't really affecting anything, but they made the output kind of obnoxious to read.
The two big things I want to focus on are: putting together the files I need to to handle installing pyproject-build in an isolated environment, because apparently that's something I need to do, and getting the rest of the functions to work with a combination of requirements file and constraints file, instead of just requirements file. Because I'm working on the Package code in tandem with the pyproject-build update, that'll get the code in the motrfile closer to ready for integration into MOTR.
I'm about done for the night, so I'll get all the thinking for this done tomorrow. For now, I should get ready for bed.